[Synthesis of somatostatin in Escherichia coli cells: isolation and characteristics]

A synthetic gene coding for somatostatin-14 (SST) was cloned in plasmid expression vectors in frame with the chloramphenicol acetyl transferase (CAT) gene, both genes being divided by a Met residue. The hybrid gene was expressed under the control of the CAT gene promoter (Pcat) or the tryptophan operon promoter (Ptrp). Them fused genes gave insoluble polypeptide products amounting from 5% of the total cellular protein under constitutive biosynthesis conditions (Pcat) to 30% upon induction (Ptrp). SST was liberated from the fused polypeptide by treatment with cyanogen bromide, purified to homogeneity by gel-filtration and reverse phase HPLC, and finally refolded by dilution and air oxidation. The renaturated recombinant SST showed the specific biological and immunological activities of the native peptide.